[meteorite-list] NWA 540

[Martinh]

Wow Bernd,

Thanks for that blast from the past. I had forgot all about post. What 
was the date on it?

I remember spending some time with a planetary geologist discussing 
this meteorite. There was no shortage of excitement as he tried to put 
together a picture of what sort of phenomena in space could create such 
a thing.

Cheers,

Martin



On Oct 19, 2004, at 11:53 AM, bernd.pauli at paulinet.de wrote:

> Martin wrote:
>
>> I posted a couple pics of a wildly melted NWA slice. This is
>> the famous NWA 540 which was first offered for sale a few
>> years ago, but then pulled completely from the market and
>> 'sold' to a Canadian museum for a very high price where it
>> will likely be preserved forever.
>
>> http://challenge.isu.edu/nwa540bw.jpg
>
>> http://challenge.isu.edu/nwa540aw.jpg
>
>> Should anyone want to purchase this amazing 132g slice
>> let me know. All serious offers will be entertained.
>
> Here is what Martin wrote when he first mentioned this meteorite
> on the Meteorite Central List:
>
> A friend of mine who is a planetary geologist took a look at an image
> of my slice of NWA 540, the one pictured above. Here are his comments:
> The images look fine. I'm not sure if the roundish inclusions are true
> chondrules or something else, perhaps CAI's? There certainly is a fair
> amount of metal. The veins contain an amorphous looking substance that
> could very well be partial melt related to an impact. They probably 
> represent
> the injection of liquid from adjacent regions, not partial melting of 
> the rock
> we see here. The rinds along the edges of these zones are fairly thin 
> and have
> sharp contacts with the host rock, meaning that the melt was chilled 
> against
> the host with minimal reaction. The host rock seems to be unaffected 
> at the
> macroscopic scale, i.e., there are not small fingers and pockets of 
> partial melt
> between more refractory inclusions. In other words, the rock was not 
> heated
> slowly to its melting point, which would cause it to melt uniformly 
> rather than
> in veins. If this was an example of in-situ magmatic melting, you 
> would probably
> see coalescent blobs of melt and tiny fractures fingering away from 
> veins or
> other zones of accumulation.
>
>
> Best regards,
>
> Bernd
>
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